New Autism diagnostic processes and tools for teens and adults

The New Zealand Autism Spectrum Guideline (2008) (the Guideline) recommends that a comprehensive assessment for the diagnosis of Autism Spectrum Disorder (ASD) will include validated diagnostic instruments administered by expert clinicians.

The most commonly used diagnostic tools in New Zealand are the ADI-R (Autism Diagnostic Interview-Revised) and ADOS (Autism diagnostic Observation Schedule). ADI-R is a semi-structured interview with demonstrated validity when administered by an experienced clinician. ADOS is considered to be the ‘gold standard’ for observational assessment of autism spectrum disorders.

The ADI-R and ADOS were reviewed by the New Zealand Living Guidelines Group, a small group of Autism Spectrum Disorder (ASD) experts who are responsible for reviewing evidence that relates to the Guideline, and reporting on the changes necessary to keep the Guideline up-to-date. Their 2011 review of diagnostic instruments for ASD can be located at http://www.health.govt.nz/publication/asd-diagnostic-instruments-review.

Since that review, two new tests that might be used for teens and adults have been developed. Each of these has demonstrated validity in preliminary evaluations. The first is a screening tool and the second is an assessment tool. A brief review follows.

1. RAADS-14 Screen

RAADS-14 Screen is a new screening tool to facilitate the diagnosis of autism in adults without intellectual disability (ID). It was developed by Associate Professor Susanne Bejerot of the Department of Clinical Neuroscience at Sweden’s Karolinska Institutet, and is intended as a tool for screening adult psychiatric outpatients for an unrecognized ASD, where comorbidities may confuse the diagnosis. RAADS-14 Screen simplified the existing 80 item self-reporting instrument, RAADS-R (Ritvo Autism and Asperger Diagnostic Scale-Revised), and includes an online test that can be located at http://psychcentral.com/quizzes/autism-quiz.htm.

An evaluation of RAADS-14 Screen was published by the test’s designers in Molecular Autism (Eriksson, Anderson & Bejerot, 2013). The participants of the study were 135 adults with ASD and no intellectual Disability, 508 subjects with some form of psychiatric disorder and 590 control subjects with no diagnosed ASD or psychiatric disorder.

This study was unique in that participants with ASD were compared with those with some form of psychiatric disorder, including ADHD and schizophrenia. Participants were scored across three domains: mentalizing deficits, social anxiety and sensory sensitivities.

The results as reported showed it is possible to clearly differentiate between those with ASD and those with psychiatric disorders, with a median score of 32 for ASD, 15 for ADHD, and 11 for other psychiatric disorders. The psychometric properties of the scale were shown to be satisfactory (Eriksson, Anderson, & Bejerot, 2013).

2. AMSE: Autism Mental Status Exam

AMSE: Autism Mental Status Exam was intended to provide brief and streamlined observational assessment for ASD in under-resourced clinical settings where the gold standard diagnostic assessment is not feasible. It was developed over three years at the Seaver Autism Center for Research and Treatment at the Icahn School of Medicine at Mount Sinai in New York City. ASME involves an eight item observational assessment and has been described as the first mental status exam that operationalizes the direct observation of social, communicative, and behavioral functioning.

Initial validation data published in the Journal of Autism and Developmental Disorders in 2012 included an unstratified sample of persons from age 18 months through 38 years and indicated excellent classification accuracy (Grodberg, Weinger, Kolevzon, Soorya, & Buxbaum, 2012). A later study investigated the sensitivity and specificity of ASME scores using DSM-5 criteria for ASD in high risk verbally fluent adults, with the high clinical utility suggesting ASME may offer a streamlined diagnostic assessment tool to support clinical diagnosis (Grodberg et al., 2014).

Where to get more information

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